Fort Collins, CO (written by Sarah Jane Kyle) -- A Colorado fire that started at about two acres early Saturday morning, has been fueled by high winds and was marked at zero percent containment late Saturday evening.

The High Park Fire, which burns 15 miles west of Fort Collins, has been fueled by rugged terrain, dry conditions and low humidity. The Larimer County (Colo.) Sheriff's office put the size of the fire at 14,000 acres.

Colorado Gov. John Hickenlooper said at least one third of all national firefighting resources are being utilized to combat the fire.

Evacuation remains a top priority as crews continue to battle what officials say could be the worst fire to date in Larimer County.

"I've been with Poudre Fire Authority 24 years and this is the largest fire I've seen," said Fire Chief Tom DeMint.

During an afternoon news conference, Larimer County Sheriff Justin Smith said that firefighters have "No hope for containment. Mother Nature is driving ... we just have to get people out of its way."

Earlier Smith said that crews have narrowed reports of missing persons to one unconfirmed report of a resident "not making it out." Later Sunday, sheriff's officials confirmed that one person is missing from a home that was destroyed.

The identity of the missing person has not been released, and crews continue the search. No further injuries have been reported, though one firefighter was removed from the scene Saturday for heat exhaustion.

Sheriff's officials have issued 1,900 emergency notifications, saying that most evacuations have gone smoothly, but some residents are refusing to leave their homes.

"Evacuation is paramount," DeMint said. "Follow those orders."

Predictions for the fire's potential growth remain in the air, with large portions of "unburned fuel" remaining in the horseshoe-shaped burn area, Smith said.

Hickenlooper is hopeful the weather conditions will change. "We're going to throw everything we can at it," he said. "But nature is our biggest resource. More equipment would help, but we can only do so much to fight a fire of this size. Nature is conspiring against us."

Some evacuation crews and firefighters have been on duty for at least 24 hours.

Smith said replacement crews are making their way and will provide some relief, but resources are limited with a large fire in New Mexico and other fire concerns.

"You never have enough resources in something like this, but everyone here is doing everything they can," Smith said.

According to a sheriff's report, more resources have been ordered, including military air support.

At least 18 structures have been lost or damaged and others are threatened, according to a tweet by the Larimer County Sheriff's Office. No details are currently available about those structures.